If you manage to get to Portmeirion, and would like to see a little more of Clough Williams Ellis's architecture, you can go and have a look at his private gardens at Plas Brondanw. There is castle folly you can explore, that he built up on the hill as a homage to the fire fighters who saved his home from fire and sometimes, his house is open to the public too, but check on their website for dates.
From there, it's a beautiful drive onto Beddgellert, where you can have lunch by the river and learn how Beddgellert got it's name. It's a stunningly beautiful area.